Mr Nash said it would give ratepayers a say in what happens in their districts and cities, unlike the super-city structure forced on people in Auckland.
He said he will now lobby parties and MPs, including contacting every mayor in the country to urge them to lobby their MPs to support the bill.
He's already contacting potential supporters in Parliament, buoyed by Wednesday's close vote on a member's bill from New Zealand First leader Winston Peter seeking three free doctor's visits a year for the over 65s.
It was defeated by just a single vote.
A Better Hawke's Bay, the group which initiated the LGCs proposal, argues Mr Nash's bill is "fundamentally flawed".
Founding member Rebecca Turner said it would mean the "14 or so" constituents in the Rangitikei Regional Council area - the only eligible voters not from Wairoa, Napier, Hastings or Central Hawke's Bay - would be able to stop the wishes of the majority of Hawke's Bay people.
"It seems like all this bill does is stop the democratic right of the entire region," she said.
"This is exactly why A Better Hawke's Bay pushed for a vote, so Hawke's Bay people can decide whether they want amalgamation of our councils. Stuart Nash's bill would give the people of Rangitikei the power to block the wishes of all the other 110,000 voters in Hawke's Bay."